EXOTIC TREES IN GREAT BRITAIN 133
century. It is a common tree of parks and gardens and, accord-
ing to Carter, is almost naturalised in the south-western counties.
The Turkey Oak (Q. cerris L.) was introduced about 1735 and is
another stately tree whose home is south-eastern Europe and
Asia Minor. In Britain it is very hardy and grows rapidly. It
appears to be naturalised in some parts of Britain and certainly
there are some fine trees in Epping Forest, apparently wild.
No account of our exotic trees, however incomplete, ought to
omit mention of the London Plane (Platanus acerifolia Willd.)
for it is as cockney as the House Sparrow. It is a hardy tree of
rapid growth and is the commonest London tree. Its origin is
unknown and it has never been found wild; it is thought to be a
hybrid between the Oriental Plane (P. orientalis L.), an uncommon
tree in Britain, and the Buttonwood (P. occidentalis L.) of the
U.S.A., a tree which is not hardy in this country. Probably no
tree is so tolerant of a smoke-laden atmosphere and, since the
London Plane is a fine shade tree as well, its popularity for town
planting is not surprising. With the London Plane one ought to
associate that other exotic which does so well in towns—the
Tree of Heaven (Ailanthus altissima Swingle), a native of China
and introduced here in the middle of the 18th century. It is by
no means as common as the London Plane but is hardy in the
south. It grows rapidly and when mature has a beautiful form.
Only female trees can be planted in towns, for the male flowers
have a smell which the populace—its olfactory sense attuned to
the reek of petrol fumes and other urban aromas—finds un-
pleasant.
At the conclusion of my address I am well aware that a critic
might object to the apparently disproportionate amount of
space which I have devoted to the conifers, which are, after all, a
small group of plants. This seems justified for although exotic
broad-leaved trees in Britain far outnumber, in species, the
conifers, it is the latter which play a more prominent part in our
landscape. The conifers, in contrast with most broad-leaved
trees, are essentially gregarious and are more likely to occur in
groups and, moreover, they are the trees which interest the
forester as in general yielding the timber which we can afford to
grow in this country.
BIBLIOGRAPHY
Ackers, C. P. 1947. Practical British Forestry. Oxford.
Bean, W. J. 1929. Trees and Shrubs Hardy in the British Isles. London.
Boulton, E. H. B. and Jay, B. A. 1946. British Timbers. London.
D.S.I.R. (Forest Products Research). 1941. A Handbook of Home-grown
Timbers. London.